The invention relates to a turbine for an exhaust gas turbocharger having a spiral channel for supplying exhaust gas to a turbine wheel and being provided with an annular blocking element which surrounds the turbine wheel and is rotatably supported for controlling the admission of exhaust gas to the turbine wheel and also to an exhaust gas turbocharger having such a turbine.
DE 25 39 711 A1 discloses a spiral housing for turbomachines, in particular in an exhaust gas turbocharger, having a cross section which is adjustable at least in parts, at least one tongue being provided which is slidingly guided at the radially inner wall of the spiral housing and displaceable in connection with this wall in the peripheral direction.
An internal combustion engine for a motor vehicle is known from DE 10 2008 039 085 A1 having an exhaust gas turbocharger which includes a compressor disposed in an intake tract of the internal combustion engine and a turbine in an exhaust tract of the internal combustion engine. The turbine has a turbine housing which includes a spiral channel which is coupled to an exhaust line of the exhaust tract. A turbine wheel is situated within an accommodation space in the turbine housing, and a compressor wheel of the compressor is connected to the turbine wheel in a rotationally fixed manner via a shaft and may be acted on by exhaust gas of the internal combustion engine The turbine includes an adjusting device by means of which a spiral inlet cross section of the spiral channel as well as a nozzle cross section of the spiral channel are jointly adjustable with respect to the accommodation space.
To keep the fuel consumption of internal combustion engines, and thus their CO2 emissions, low, the internal combustion engines are provided with charging devices so that the internal combustion engines are suppliable with compressed air, which by means of the exhaust gas of the internal combustion engine is compressed via a corresponding exhaust gas turbocharger. Thus, the internal combustion engines may be designed according to the so-called downsizing principle, which means that the internal combustion engines have a relatively small volume but are able to provide particularly high power and torque. Thus, the internal combustion engines have very high specific power and torque. As a result, the requirements for the charging devices are continually increasing, in particular with regard to adaptability of the charging devices to different operating points so that efficient operation of the charging devices is achievable.